Anatomy of the Dicotyledons.
About: This article is published in American Midland Naturalist.The article was published on 1950-11-01. It has received 2511 citations till now.
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TL;DR: The epidermal structure and ontogeny of stomata are described in 31 species of the Acanthaceae and the stomatalOntogeny is syndetocheilic or mesogenous and is similar for different organs of the same plant.
Abstract: The epidermal structure and ontogeny of stomata are described in 31 species of the Acanthaceae. The epidermal cells are polygonal, isodiametric, or elongated with thick, sinuous, arched, or straight anticlinal walls. Extrafloral nectaries and nine types of glandular and eglandular trichomes have been observed. Needle-like, rodlike, and square crystals of calcium oxalate have been observed in the hair cells. The mature stomata are typically caryophyllaceous with two to four subsidiary cells and are formed in three to five successive mitotic divisions of the meristemoid. The stomatal ontogeny is syndetocheilic or mesogenous and is similar for different organs of the same plant. Abnormal stomata with a single guard cell, aborted guard cells, or arrested development are frequent.
26 citations
TL;DR: Continuity between the gynoecial primordia is reached earlier in the Plumbagoideae than in the Armerioideae, and in the centre of the ovary a primordium arises that develops into the single basal circinotropous bitegmic ovule.
Abstract: A scanning electron microscopic study of the floral ontogeny of seven species of the Plumbaginaceae (representing five genera of the Armerioideae and two of the Plumbagoideae) is presented. The early ontogenetic stages in all species examined are sufficiently similar to propose the following familial description. The five sepal primordia are initiated simultaneously or spirally. These soon reach continuity and develop into the synsepalous calyx. Meanwhile, five common stamen-petal primordia that alternate with the sepal primordia are initiated simultaneously on the flattened apex. Soon, two distinct growth-centres can be observed on each of these primordia: a petal primordium at the abaxial side and a stamen primordium on the top. After inception of the common primordia, five gynoecial primordia alternating with the common primordia are initiated simultaneously on the corners of the apex that has become pentagonal. These primordia soon reach continuity and develop into the superior unilocular gynoecium. Continuity between the gynoecial primordia is reached earlier in the Plumbagoideae than in the Armerioideae. In the centre of the ovary a primordium arises that develops into the single basal circinotropous bitegmic ovule. The floral nectaries are associated with the androecium.
25 citations
TL;DR: Variation in trichome characters appears to have particular value, not only in classification at sectional rank, but also in separating different species of Phlomoides from their relatives.
25 citations
TL;DR: Inflorescence morphology provides characters of systematic significance for various taxa within core Malvales and represents one of the rare morphological synapomorphies of coreMalvales.
Abstract: A broad comparative analysis reveals that the inflorescences of coreMalvales, familiesSterculiaceae, Tiliaceae, Bombacaceae andMalvaceae, include characteristic repeating units. The basic repeating unit is called bicolor unit (afterTheobroma bicolor, where it was first observed). It is determinate and bears three bracts, one of which is invariably sterile, whereas the others subtend lateral cymes or single flowers. Through the demonstration of intermediate steps in closely related taxa the triad of bracts within a bicolor unit and the trimerous malvalean epicalyx are shown to be homologous. Various possibilities for an origin of the bicolor unit are discussed. Bicolor units are variously arranged to form complete inflorescences. In many taxa they are terminal on modules that comprise two (or fewer) prophylls. These modules may be arranged in elongated anthocladia or condensed sympodia, which in turn may constitute components of higher order inflorescence structures. The presence of the bicolor unit or its derivatives linksSterculiaceae, Tiliaceae, Bombacaceae andMalvaceae. It is absent from all other families included in a broader defined orderMalvales and represents one of the rare morphological synapomorphies of coreMalvales. Furthermore, inflorescence morphology provides characters of systematic significance for various taxa within coreMalvales.
25 citations
TL;DR: In this paper, the identification of charcoal origin through anatomical analysis of Eucalyptus and Corymbia wood samples was done according to IAWA Committee and the results on charcoal are very close to previous studies of wood anatomy.
Abstract: Charcoal is one of the main forestry products and Brazil is the world’s largest producer. Its production from native species is estimated at 30-35% of total output. One of the major problems of the iron and steel industry is charcoal consumption, especially in terms of environmental and social aspects. Therefore, the use of reforestation species must be increased. Considering most of the energy forests in Brazil are planted with eucalyptus, the present work aims to contribute to the identification of charcoal origin through anatomical analysis of Eucalyptus and Corymbia. The wood samples were carbonized in a muffle furnace during 7h to a maximum of 450oC. Anatomical analysis was done according to IAWA Committee. We found few works with charcoal anatomy and the species analyzed were not characterized. The results on charcoal are very close to previous studies of wood anatomy. But, we recommend the comparison of materials of similar features, enhancing the visual acuity, particularities of each material and modifications that might happen. We believe that this analysis is an accurate tool to identify the source of charcoal and can help to guarantee the sustainability of the charcoal supply chain.
25 citations
Cites background from "Anatomy of the Dicotyledons."
...These differences are common within genera (Metcalfe and Chalk 1950, Carlquist 2001), and especially in the case of growth rings, they are also influenced by ecological factors, particularly water supply (Carlquist 2001, Schweingruber 2007)....
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